CREEK CHUB 



inches in length, the number per 

 pound was reduced to 100 fish. In 

 some ponds where overstocking had 

 occurred, the minnows at the end of 

 the growing season had an Average 

 length of 11/2 inches. It was 

 learned that when these unsalable 

 fish were returned to growing 

 ponds the next year, it took several 

 weeks before growth was resumed. 

 It seems that these fish had been 

 stunted the previous year by the 

 crowded condition. From this ex- 

 perience it is suggested that an op- 

 erator should be careful and not 

 stock his ponds at the maximum 

 rate. 



The following table presents the 

 number of creek chubs of various 

 lengths to the pound and gallon- 



''■ 1 gaHon equals 8 pounds. 



Spawning 



Creek-chub breedere should be in- 

 troduced into the raceway when the 

 species is known to be spawning in 

 nearby natural waters. If a check 

 cannot be kept on natural spawn- 

 ing, or if no natural spawning oc- 

 curs in the area, it is advisable to in- 



troduce the fish when the water 

 temperature in the raceway has 

 reached 55° F. for a 2- or 3-day 

 period. Creek chubs usually start 

 to spawn during the latter part of 

 April in waters north of an imagi- 

 nary line drawn east and west from 

 the Michigan-Ohio border. Spawn- 

 ing is terminated late in May or 

 early in June in the Lake Superior 

 area, but continues into July in 

 northern Minnesota. The nesting 

 season for any one locality usually 

 lasts about 3 weeks. 



At one commercial hatchery, it 

 was noted that the breeder chubs 

 used the spawning raceway for 

 about a 3-week period. During the 

 first few^ days, the population of 

 breeders steadily increased until a 

 maximum number was present on 

 about the seventh day. At this time 

 about 4,000 breeders were occupy- 

 ing the raceways. Following this 

 peak, the number of breeders de- 

 creased daily until only about 100 

 were left at the end of the 3-w^eek 

 period. During the early part of 

 the spawning period, the male chubs 

 select areas in the raceways well iso- 

 lated from one another. Later, 

 however, there is considerable pi- 

 rating among the redds — the in- 

 creased population of breeders 

 bringing on additional competition 

 for space. It is estimated that at 

 least 50 percent of the redds are de- 

 stroyed in this manner during the 

 spawning season. Many dead chubs 

 of both sexes collect on the surface 

 of the brood pond within a week 

 after the onset of spawning activity. 

 By keeping a careful record of the 



91 



